Dialysis catheter

ABSTRACT

A dialysis catheter comprising a catheter body having a proximal portion, a distal portion, a first longitudinally extending central lumen configured to deliver blood, and at least three longitudinally extending lumens positioned radially of the central lumen and configured to withdraw blood from a patient. At least one blood delivery opening is formed in the distal portion of the catheter body and in fluid communication with the first lumen and configured for passage of blood therethrough. At least three blood withdrawal openings are formed in the outer wall of the catheter body, wherein each of the openings is in fluid communication with one of the at least three lumens and is configured for passage of blood from a patient

BACKGROUND

This application claims priority from provisional patent applicationSer. No. 60/260,592, filed Jan. 9, 2001, the entire contents of which isincorporated herein by reference.

TECHNICAL FIELD

This application relates to a catheter and more particularly to amulti-lumen catheter which facilitates hemodiaylsis.

BACKGROUND OF RELATED ART

Hemodialysis is a well known method of providing renal (kidney) functionby circulating blood. The kidneys are organs which function to extractwater and urea, mineral salts, toxins, and other waste products from theblood with filtering units called nephrons. From the nephrons thecollected waste is sent to the bladder for excretion. For patientshaving one or both defective kidneys, the hemodialysis procedure is lifesaving because it provides a machine to simulate the function of thekidneys.

In the hemodialysis procedure, blood is withdrawn from the patient'sbody through a catheter or tube and transported to a dialysis machine,also commonly referred to as a kidney machine. The catheter is typicallyinserted through the jugular vein and maneuvered into position throughthe superior vena cava into the right atrium to provide high blood flow.In the dialysis machine, toxins and other waste products diffuse througha semi-permeable membrane into a dialysis fluid closely matching thechemical composition of the blood. The filtered blood, i.e. with thewaste products removed, is then returned to the patient's body. In someinstances, the catheter may be left in place for several years. As canbe appreciated, proper access to the patient's blood and transport ofthe blood to and from the dialysis machine for this extended period oftime is critical to hemodialysis.

One example of a dialysis catheter currently being marketed is theMedComp Ash Split catheter. This catheter has two lumens, one forarterial flow and the other for venous flow, which are each D-shaped incross-sectional configuration. The catheter is bifurcated at its distalend to separate the lumens and the catheter is manually split to thedesired length for selected separation before insertion into the targetarea. Another well-known catheter is a Med Comp catheter which has thevenous flow lumen terminating proximally, i.e. axially recessed, fromthe arterial flow lumen. Each of these lumens is also D-shaped incross-sectional configuration.

These Medcomp dialysis catheters require numerous steps for insertion.The multiple insertion steps can be summarized as follows:

-   -   1. an introducer needle is inserted through a first incision        site (first opening) to properly locate (access) the vessel,        e.g. the right internal jugular vein;    -   2. a guide wire is inserted through the needle into the internal        jugular vein and down through the superior vena cava into the        inferior vena cava;    -   3. the introducer needle is withdrawn leaving the guidewire in        place;    -   4. a tear away (peel away) sheath and dilator are inserted over        the guidewire and through the first incision site to provide an        access port for the dialysis catheter into the jugular vein,        superior vena cava and right atrium;    -   5. a second incision is made in the chest wall to create a        second opening;    -   6. a trocar is attached to the distal end of the dialysis        catheter;    -   7. the trocar and dialysis catheter are pushed through the        second incision and advanced to bluntly dissect the subcutaneous        tissue to exit the first incision (opening) which was created by        the introducer needle, thereby creating a subcutaneous tissue        tunnel between the first and second openings;    -   8. the trocar is detached from the dialysis catheter leaving the        catheter in place extending from the second opening, through the        tissue tunnel and out the first opening;    -   9. the dilator and guidewire are removed, leaving the tear away        sheath in place in the first incision which has been expanded by        the dilator;    -   10. the dialysis catheter, which is protruding from the first        incision, is inserted through the tear away sheath and advanced        so its distal portion is positioned in the right atrium;    -   11. the sheath is separated, i.e. split, by pulling the tabs        apart, and then pulled upwardly away from the dialysis catheter        and removed from the body, leaving the catheter in place; and    -   12. the second incision is closed and the dialysis catheter,        which is connected through tubes to the dialysis machine, is        left in place an extended period of time to provide blood        circulation to and from the dialysis machine.

(Alternatively, in the foregoing method, the trocar can be forcedthrough a third incision exiting adjacent the first incision, and theninserted through the introducer sheath positioned in the firstincision.)

This multiple step process of inserting the Medcomp dialysis catheter istime consuming and complicates the surgical procedure. These multiplesteps add to the cost of the procedure, not only because of theadditional surgeon's time but because additional components, such as thetear-away sheath, are required which increases the overall cost of thecatheter system. Also, removal of the dilator increases the tendency ofthe sheath to kink causing difficulties in catheter insertion.

The use of the tear away sheath is also potentially problematic. Thetear-away style sheath has lines of weakness to separate the sheath asit is pulled apart by the pull tabs to enable removal of the sheath.However, the sheath can potentially cause damage to the vessel wall asit is being pulled apart and can cause infection. Moreover, pulling thesheath laterally can enlarge the incision, thereby increasing thedifficulty of closing the incision at the end of the procedure. Also,since the sheath is pulled in the proximal direction for removal, itcould pull the catheter proximally as well, thereby pulling it away fromthe desired site, and requiring repositioning. The edges of the tearaway can also lacerate the surgeon's glove and finger.

An additional potential risk with utilizing tear away sheaths is thatair embolism can occur. During the time the surgeon withdraws thedilator from the sheath and inserts the catheter, a passageway throughthe sheath to the vessel is open. If the patient inhales during thiscatheter exchange, an air bubble can enter the vascular system andobstruct the vessel, potentially causing stroke or even death.

It would therefore be advantageous if a dialysis catheter insertionmethod could be provided which reduces some of the foregoing proceduralsteps, thereby decreasing the complexity of the procedure and decreasingthe hospital and surgeon costs. It would also be advantageous if suchdialysis catheter insertion method could be provided which would be lesstraumatic and avoid the foregoing problems associated with the use of atear-away sheath, such as increased risk of air embolism, trauma to thevessel wall, incision enlargement and dislodgement of the catheter.

Another area of dialysis catheter insertion, which needs improvement, isguiding the catheter to the target site. Dialysis catheters are composedof flexible tubing to minimize damage to the vessel wall duringinsertion and use. This flexibility, however, oftentimes results inkinking of the catheter since the catheter must navigate curves to reachthe target vessel. This kinking can adversely affect blood flow. Also,the catheter needs to have some degree of stiffness to enable directingthe catheter around the curves of the vessels. The stiffness, howeverprovides its own risks since if the catheter is not properly directed,the catheter can inadvertently be forced against the vessel wall,thereby puncturing or damaging the vessel. Several different approacheshave been discussed in the prior art to increase stiffness of catheterssuch as providing a distal tip of stiffer material to guide the catheteras in U.S. Pat. No. 5,957,893, using materials of different durometersin various portions of the catheter (U.S. Pat. No. 5,348,536), placingan additional concentration of material in the tip as in U.S. Pat. No.4,583,968, or providing reinforcing strips, obturators or tubes withinthe catheter body to increase the rigidity (e.g. U.S. Pat. Nos.4,619,643, 4,950,259 5,221,255, 5,221,256, and 5,246,430). The needhowever exists to improve the balance between flexibility and stiffness.Thus it would be advantageous to provide a catheter with sufficientflexibility to accommodate anatomical curves of the patient while stillhaving sufficient stiffness to enable guiding the flexible cathetertubing atraumatically through the length of the vessels.

In navigating vessels to access the target site, such as the rightatrium, it is desirable to provide the smallest catheter profile, i.e.the smallest outer diameter catheter body. This profile facilitatesinsertion through smaller vessels as it reduces the likelihood of thecatheter engaging the wall of the vessel and reduces trauma to thevessel by minimizing frictional contact with the vessel wall. However,the desire for smaller diameter catheters must be balanced against theneed for providing sufficient sized lumens to enable proper blood flow.If the lumens are too small, sufficient blood flow may not be able to bemaintained and the blood can be damaged during transport. Also, asufficient relationship must be maintained between the size of thelumens and the overall diameter of the catheter to maintain thestructural integrity of the catheter.

Numerous attempts have been made in the prior art to optimize themulti-lumen configuration. In some approaches, such as disclosed in U.S.Pat. Nos. 4,568,329 and 5,053,023, inflow and outflow lumen are providedside by side in D-shaped form. In other approaches, such as thosedisclosed in U.S. Pat. Nos. 4,493,696, 5,167,623 and 5,380,276 theinflow and outflow tubes are placed in concentric relation. Otherexamples of different lumen configurations are disclosed in U.S. Pat.Nos. 5,221,256, 5,364,344, and 5,451,206. The lumen configuration mustaccommodate two competing factors: keeping the catheter as small aspossible to facilitate insertion while keeping the lumens as large aspossible for blood flow. This balance must be achieved while maintainingthe structural integrity of the catheter. It would therefore beadvantageous to provide a catheter which reaches an optimum compromisebetween these two competing factors.

Another important feature of dialysis catheters is the suction openingsto withdraw blood. Keeping the suction openings clear of thrombolyticmaterial and away from the vessel wall is clearly essential to dialysisfunction since an adequate supply of blood must be removed from thepatient to be dialyzed. However, a problem with prior dialysis cathetersis that during blood withdrawal, as suction is being applied through thecatheter openings and lumen, the suction can cause the catheter to beforced against the side wall of the vessel, known as “side portocclusion”, which can block the opening and adversely affect thefunction of the catheter by enabling only intermittent suction. In fact,the opening can become completely blocked, thereby preventing necessaryintake of blood, i.e. venous flow. Fibrin sheath growth around theoutside of the catheter can occur since dialysis catheters areoftentimes implanted for several months or even years. This fibringrowth, caused by the body's attempt to reject the catheter as a foreignbody, could result in blocking of the suction holes.

The need therefore exists for an improved dialysis catheter whichfacilitates the surgical dialysis procedure. Such catheter wouldadvantageously reduce the catheter insertion time, simplify the catheterinsertion process, eliminate the need for a peel-away introducer sheath,decrease the chances of infection, reduce unwanted kinking of thecatheter during insertion, strike an optimal balance between overallcatheter and lumen size, and improve the suction capability to avoidhampering of venous flow.

SUMMARY

The present invention overcomes the disadvantages and deficiencies ofthe prior art. The present invention provides a dialysis cathetercomprising a catheter body having a proximal portion, a distal portion,a first longitudinally extending central lumen configured to deliverblood, and at least three longitudinally extending lumens positionedradially of the central lumen and configured to withdraw blood from apatient. At least one blood delivery opening is formed in the distalportion of the catheter body and in fluid communication with the firstlumen and configured for passage of blood therethrough. At least threeblood withdrawal openings are formed in the outer wall of the catheterbody, wherein each of the openings is in fluid communication with one ofthe at least three lumens and is configured for passage of blood from apatient.

Preferably, the blood withdrawal side openings are spaced proximally ofthe blood delivery opening.

In one embodiment, the first lumen is substantially circular in crosssection and each of the at least three longitudinally extending lumensis substantially oval in cross section, wherein the substantially ovalcross section lumens each are defined by first and second curvedopposing walls and second and third substantially linear opposing walls.In an alternate embodiment the at least three longitudinally extendinglumens are substantially rectangular in cross section. In anotherembodiment, the first lumen is substantially rectangular in crosssection and each of the at least three longitudinally extending lumensis substantially oval-like in cross section.

A stiffening member may be provided which is positionable within thecatheter in abutment with a shoulder or threadedly attached in analternate embodiment. The stiffening member places the catheter body intension, and torquing the stiffening member stretches the catheter bodyto reduce at least a portion of an outer diameter of the catheter body.A stiffening insert can also be provided having a lumen formed thereincommunicating with the first lumen.

The present invention also provides a catheter for delivering andwithdrawing blood from a patient's body comprising a catheter bodyhaving an outer wall, a distal tip portion, a first lumen extending froma proximal portion of the catheter body through the distal tip portionand configured to receive a guidewire therein, first and secondlongitudinally extending lumens independent of the first lumen, andfirst and second radially spaced openings in the outer wall, eachopening in fluid communication with a respective longitudinallyextending lumen. A stiffening insert is positioned in the distal tipportion and has a first stiffness greater than a second stiffness of thedistal tip portion and has a lumen therethrough communicating with thefirst lumen extending through the distal tip portion.

The distal tip portion has a bullet nose configuration in one embodimentand tapers to a reduced diameter region in another embodiment. In oneembodiment, least two side ports are formed in an outer wall of thedistal tip portion and are in fluid communication with the first lumenof the distal tip portion and positioned proximally of the stiffeninginsert.

The present invention also provides a catheter for delivering andwithdrawing blood from a patient's body comprising a catheter bodyhaving an outer wall, a distal portion, a central lumen extending from aproximal portion of the catheter body to the distal portion andconfigured to receive a guidewire therein and to allow blood passagetherethrough, and at least three longitudinally extending lumensindependent of the central lumen and radially displaced with respect tothe central lumens. At least three openings are formed in the outer wallof the catheter body, each opening being in fluid communication with oneof the at least three longitudinally extending lumens. A stiffeningmember is removably positionable within the central lumen and removablymountable to a portion of the catheter. The stiffening member includes alongitudinally extending lumen for receiving a guidewire.

In one embodiment, the stiffening member terminates proximally of thedistalmost tip of the catheter; in another embodiment it extendsdistally of the distalmost tip.

The stiffening member preferably has a threaded portion on its proximalend portion for mounting the stiffening member to the catheter and fortorquing the stiffening member to stretch the catheter body. In oneembodiment, the stiffening member has a threaded portion at its distalportion for mounting a distal portion to the catheter body. In anotherembodiment, the stiffening member has an abutment tip for abutting ashoulder formed internally at the distal tip portion to limit insertionof the stiffening member. The shoulder may be formed by the distalportion having first and second internal lumens communicating with thecentral lumen of the catheter body wherein the first lumen has a smallerdiameter than the second lumen.

The present invention also provides a system for placement of a dialysiscatheter comprising a tunneling trocar and a dialysis catheter. Thesystem comprises a trocar having an elongated tubular portion and alumen extending longitudinally through the tubular portion. The tubularportion terminates in a dilating tip configured to dilate tissue andcreate a subcutaneous tissue tunnel. The lumen has a first internaldiameter configured to removably receive a guidewire therethrough forretrieval of the guidewire. The dialysis catheter has a first lumenconfigured for blood delivery and a second independent lumen configuredfor blood withdrawal from the patient. At least a portion of thecatheter has an outer diameter configured for insertion through thesubcutaneous tissue tunnel and one of the lumens is configured toreceive the guidewire for over the wire insertion of the dialysiscatheter through the tissue tunnel when the trocar is removed.

The present also provides a catheter for delivering and withdrawingblood from a patient's body comprising a catheter body having an outerwall, a distal portion, a central lumen extending from a proximalportion of the catheter body to the distal portion and configured toreceive a guidewire therein and to allow blood passage therethrough, andat least three longitudinally extending lumens independent of, andradially displaced with respect to, the central lumen. At least threeopenings are formed in the outer wall of the catheter body, each openingbeing in fluid communication with one of the at least threelongitudinally extending lumens. A first intermediate tube extends froma proximal end of the central lumen and second, third and fourthintermediate tubes each extend from a proximal end of one of the atleast three lumens. A first extension tube having a lumen formedtherethrough communicates with the first intermediate tube and a secondextension tube having at least three lumens formed therethroughcommunicates with the second, third and fourth intermediate tubes.

The present invention also provides a method of inserting a dialysiscatheter into a patient comprising:

-   -   inserting a guidewire into the jugular vein of the patient        through the superior vena cava, and into the inferior vena cava;    -   providing a trocar having a lumen and a dissecting tip;    -   inserting the trocar to enter an incision in the patient to        create a subcutaneous tissue tunnel;    -   threading the guidewire through the lumen of the trocar so the        guidewire extends through the first incision;    -   providing a dialysis catheter having first and second lumens;    -   removing the trocar; and    -   inserting the dialysis catheter over the guidewire through the        incision and through the jugular vein and superior vena cava        into the right atrium.

The method may further comprise the step of temporarily inserting astiffening member in the first lumen of the catheter to facilitateinsertion of the catheter and twisting the stiffening member andsecuring the stiffening member to a proximal portion of the catheter tostretch the catheter to reduce at least a portion of the outsidediameter of the catheter.

The present invention also provides a method of inserting a dialysiscatheter into a right atrium of a patient comprising:

-   -   providing a dialysis catheter having a lumen;    -   inserting a guidewire into the internal vena cava of the        patient;    -   inserting a stiffening member through the lumen in the catheter;    -   inserting a guidewire through the stiffening member and        advancing the dialysis catheter and stiffening member over the        guidewire into the vein and into the right atrium of the        patient;    -   removing the guidewire leaving the dialysis catheter in place        for a period of time.

The method may further comprise the step of inserting the stiffeningmember so its dilating tip extends distally of the catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiment(s) of the present disclosure are described hereinwith reference to the drawings wherein:

FIG. 1 is a plan view of a first embodiment of the multi-lumen catheterof the present invention being inserted through the right internaljugular vein and superior vena cava into the right atrium of a patient'sbody;

FIG. 2 is a plan view illustrating the multi-lumen catheter of FIG. 1being inserted through the left internal jugular vein and superior venacava into the right atrium;

FIG. 3 is an isometric view of the first embodiment of the multi-lumencatheter of the present invention and showing the direction of insertionof the stiffening rod;

FIG. 4A is a side view of a first embodiment of a stiffening rod of thepresent invention insertable through the catheter of FIG. 3 tofacilitate catheter insertion;

FIG. 4B is a side view of an alternate embodiment of the stiffening rodof the present invention having a series of mounting threads at itsdistal end;

FIG. 5 is perspective view of the distal portion of the multi-lumencatheter of FIG. 3 and showing a guidewire extending through the centrallumen;

FIG. 6A is a longitudinal cross-sectional view taken along lines 6A-6Aof FIG. 5;

FIG. 6B is a longitudinal cross-sectional view similar to FIG. 6A exceptshowing an alternate embodiment of the catheter having internal threadsfor securing the stiffening rod of FIG. 4B;

FIG. 7 is a transverse cross sectional view taken along lines 7-7 ofFIG. 6A;

FIG. 8 is a transverse cross sectional view taken along lines 8-8 ofFIG. 6A:

FIG. 9A is a transverse cross-sectional view similar to FIG. 8 exceptshowing a second alternate embodiment of the lumen configuration of thecatheter of the present invention;

FIG. 9B is a transverse cross-sectional view similar to FIG. 8 exceptshowing a third embodiment of the lumen configuration of the catheter ofthe present invention;

FIG. 9C is a transverse cross-sectional view similar to FIG. 8 exceptshowing a fourth embodiment of the lumen configuration of the catheterof the present invention;

FIG. 10 is a transverse cross-sectional view similar to FIG. 8 exceptshowing a fifth embodiment of the lumen configuration of the catheter ofthe present invention;

FIG. 11 is a longitudinal cross sectional view of the distal end portionof the catheter of FIG. 3 illustrating the stiffening rod of FIG. 4Abeing inserted through the central lumen of the catheter;

FIG. 12 is a longitudinal cross sectional view similar to FIG. 11 exceptshowing the stiffening rod fully positioned within the central lumen, inabutment with the stop in the distal tip;

FIGS. 13-15 illustrate an alternate embodiment of the distal tip of thecatheter of the present invention and the method steps for forming thetip wherein:

-   -   FIGS. 13A and 13B are perspective and cross-sectional views,        respectively, of the tip before formation shown receiving a        stiffening insert;    -   FIGS. 14A and 14B are perspective and cross-sectional views,        respectively, of the tip once the stiffening inserted has been        placed therein;    -   FIGS. 15A and 15B are perspective and cross-sectional views,        respectively, of the distal tip formed into a bullet nose        configuration and showing side holes formed therein;

FIG. 16A is a perspective view of a distal portion of another alternateembodiment of the multi-lumen catheter of the present invention having aseries of spacer wires and showing a guidewire extending therethrough;

FIG. 16B is a longitudinal cross-sectional view of the distal portioncatheter of FIG. 16A showing the spacer wires in the extended position;

FIG. 16C is a longitudinal cross-sectional view similar to FIG. 16Aexcept showing the profile of the spacing wires and catheter bodyreduced as the stiffening rod of FIG. 4A is inserted into the centrallumen over the guidewire to stretch the catheter during insertion;

FIG. 17A is a perspective view of a distal portion of yet anotheralternate embodiment of the catheter of the present invention having aseries of integral spacer ribs;

FIG. 17B is a longitudinal cross-sectional view of the distal portion ofcatheter of FIG. 17 showing the spacer ribs in the extended position;

FIG. 17C is a longitudinal cross-sectional view similar to FIG. 17Aexcept showing the profile of the spacer ribs and catheter body reducedas the stiffening rod of FIG. 4A is inserted into the central lumen tostretch the catheter during insertion;

FIG. 18 is a perspective view of a distal portion of another alternateembodiment of the multi-lumen catheter of the present invention having atapered tip;

FIG. 19 is a longitudinal cross-sectional view of the distal portion ofthe catheter of FIG. 18 showing the stiffening rod positioned throughthe central lumen of the catheter over the guidewire;

FIG. 20 is a perspective view of a distal portion of yet anotheralternate embodiment of multi-lumen catheter of the present invention;

FIG. 21 is a perspective view of a first embodiment of a trocar of thepresent invention having a barbed proximal end for attachment to thecatheter for creating a subcutaneous tissue tunnel and for pulling thecatheter through the tissue tunnel;

FIG. 22 illustrates an alternate embodiment of the trocar of the presentinvention having a lumen for receiving a guidewire;

FIG. 23 illustrates the trocar of FIG. 22 being withdrawn after asubcutaneous tissue tunnel has been created;

FIG. 24A is a bottom view of another alternate embodiment of the trocarof the present invention having a lumen for receiving a guidewire;

FIG. 24B is a longitudinal cross-sectional view of the distal endportion of the trocar of FIG. 24A;

FIGS. 25-28 illustrate the surgical method steps for inserting themulti-lumen catheter of FIG. 3 through the right internal jugular veinand superior vena cava into the right atrium wherein:

-   -   FIG. 25 shows the introducer needle being inserted through the        right jugular vein and the guidewire being inserted through the        right jugular vein, through the superior vena cava and into the        right atrium;    -   FIG. 26 illustrates the needle introducer removed leaving the        guidewire in place in the right internal jugular vein, superior        vena cava and right atrium;    -   FIG. 27 illustrates the trocar of FIG. 22 being inserted through        a first incision site and exiting a second incision site to        create a subcutaneous tissue tunnel adjacent the incision site        for the introducer needle;    -   FIG. 28A illustrates the guidewire being threaded through the        lumen of the trocar of FIG. 22;    -   FIG. 28B illustrates the trocar being removed, leaving the        guidewire in place extending through the tissue tunnel; and    -   FIG. 28C illustrates the multi-lumen catheter of FIG. 3 inserted        over the guidewire through the tissue tunnel, and curved down        into the right internal jugular vein, superior vena cava and        right atrium;

FIGS. 29A-29G illustrate the steps for an alternate method of insertingthe multi-lumen catheter of FIG. 3 through the right internal jugularvein and superior vena cava into the right atrium wherein the trocarcreates a tissue tunnel with an exit opening at the incision cite wherethe needle and guidewire are introduced, wherein:

-   -   FIG. 29A illustrates the trocar of FIG. 22 inserted over the        guidewire through a first incision site, creating a subcutaneous        tissue tunnel, and exiting the incision site created for        insertion of the introducer needle and guidewire;    -   FIG. 29B illustrates the trocar being removed, leaving the        guidewire in place extending through the tissue tunnel and        forming a loop adjacent the needle incision site; and    -   FIG. 29C illustrates the multi-lumen catheter of FIG. 3 being        inserted over the guidewire for passage through the tissue        tunnel;    -   FIG. 29D illustrates the catheter inserted through the        subcutaneous tissue tunnel and forming a loop corresponding to        the loop formed in the guidewire,    -   FIG. 29E illustrates the catheter extending through the        subcutaneous tissue tunnel and being inserted further along the        guidewire down into the right internal jugular vein;    -   FIG. 29F is a view similar to FIG. 29E except showing the        guidewire being removed; and    -   FIG. 29G illustrates the catheter in place extending through the        subcutaneous tissue tunnel and advanced into the right internal        jugular vein, superior vena cava and right atrium;

FIG. 30 illustrates an alternate method of retracting the guidewirethrough the subcutaneous tissue tunnel formed by the trocar;

FIGS. 31-37 illustrate a method for manufacturing a first embodiment ofthe hub of the multi-lumen catheter of FIG. 3 wherein:

-   -   FIG. 31 illustrates a slit formed in the outer wall of the        catheter;    -   FIG. 32 is a view similar to FIG. 31 except showing in phantom        the central arterial lumen of the catheter;    -   FIG. 33 is a transverse cross-sectional view taken along lines        33-33 of FIG. 32;    -   FIG. 34 illustrates a pin inserted through the slit in the outer        wall of the catheter;    -   FIG. 35 illustrates the tubing inserted over the pin;    -   FIG. 36 illustrates the injection of soft material over the pin        and catheter tube to form the catheter hub which retains the        lumen connector tubes in position;    -   FIG. 37 illustrates the hub resulting from the injection molding        process enabling one connector to communicate with the inflow        (arterial) lumen and the other connector to communicate with the        multiple outflow (venous) lumens;

FIGS. 38-40 illustrate an alternate embodiment of the hub of themulti-lumen catheter of FIG. 3 wherein;

-   -   FIG. 38 illustrates a perspective view of the proximal end of        the catheter body split into five segments to accommodate the        separate connector tubes;    -   FIG. 39 is a perspective view illustrating the connector tubes        inserted into the respective lumens of the catheter body; and    -   FIG. 40 is a transverse cross-sectional view illustrating the        cuts made in the catheter wall to form the separate segments.

FIG. 41 is a perspective view of another alternate embodiment of the hubof the catheter of the present invention having the lumen configurationof FIG. 9C;

FIG. 42 is an exploded view of the hub and tube structure of FIG. 41;

FIG. 43 is an enlarged perspective view showing the transition of thevenous holes from a substantially oval to a substantially roundconfiguration at the flared proximal portion of the catheter; and

FIG. 44 is an enlarged perspective view showing the multi-lumenextension tube tapering proximally and transitioning from substantiallycircular venous holes to substantially triangular holes.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in detail to the drawings where like reference numeralsidentify similar or like components throughout the several views, thefirst embodiment of the catheter of the present invention is designatedgenerally by reference numeral 10. The catheter 10 is typically insertedinto an area of high velocity blood flow to ensure sufficient blood canbe transported from the body for dialysis. FIG. 1 illustrates thecatheter 10 inserted through the right internal jugular vein “a”, intothe superior vena cava “b”, and into the right atrium “c”; FIG. 2illustrates the catheter 10 inserted into the left internal jugular vein“d”, into the superior vena cava “b” and into the right atrium “c”.Insertion into the right atrium, from either the right or left sideprovides the necessary high blood flow to the dialysis machine. Notethat the catheter body (catheter tube) 11 is sufficiently flexible toenable it to bend to accommodate the anatomical curves as shown.

Catheter 10 has a catheter body or catheter tube 11 having a distal endportion 31, a proximal end portion 33, and an intermediate portion 35.Distal portion 31 terminates in nose 32 which is illustrativelysubstantially conical in shape. Proximal end portion 33 includes hub 12,where the lumens formed within catheter tube 11 are connected, i.e.transition, to the respective inflow and outflow tubes, 16, 18,respectively, to enable return and withdrawal of blood for dialysis.Conventional tube clamps 17 and 19 cut off blood flow through inflow andoutflow tubes 16, 18 as desired. As used herein, the terms “inflow” and“outflow” refer to the direction of blood flow with respect to thepatient's body such that “inflow” refers to flow from the dialysismachine and delivered to the body while “outflow” refers to flowwithdrawn from the body and transported to the dialysis machine.

As shown, intermediate portion of catheter 10 extends throughsubcutaneous tissue tunnel “t”, and curves downwardly toward the targetsite, e.g. the right atrium. This tunnel “t” secures the catheter inplace for dialysis for a period of weeks, or even months, with fibrouscuff 36 (FIG. 3) enabling tissue ingrowth. The formation of the tunnel“t” and the insertion of the catheter 10 therethrough will be discussedbelow in conjunction with the discussion of the catheter insertionmethod.

It should be appreciated that although the catheter is shown emergingfrom the tissue tunnel “t” at a second incision site, preferably, thetissue tunnel would not have an exit opening at a second site butinstead would exit through the same incision through which initialaccess is made by the needle and dilator into the internal jugular vein“a”. This is described in more detail below.

A series of lumens are formed in catheter tube 11 for transporting bloodto and from a dialysis machine. As is well known in the art, a dialysismachine essentially functions as a kidney for patients suffering fromkidney failure. Blood is removed from the patient and transported to thedialysis machine where toxins are removed by diffusion through asemi-permeable membrane into a dialysis fluid. The filtered blood isthen returned through the catheter body to the patient.

More specifically, and with reference to FIGS. 5, 6A, 7 and 8, detailsof the catheter lumens will now be described. Central longitudinal lumen40 is formed within catheter tube 11, extends the entire length and isdesigned to transport filtered blood to the patient. Lumen 40 is alsoconfigured to receive a guidewire 20 to direct the catheter to thedesired position. Lumen 40 extends to nose 42, and terminates in region37 where it aligns with central longitudinal lumen 41 of nose 42.Central lumen 41 of nose 42 communicates with narrowed lumen 45,terminating in distal opening 47 to communicate with the patient's bodyso blood can be delivered through distal opening 47. Lumens 41 and 45also receive guidewire 20. Thus, lumen 40, lumen 41 and narrowed lumen45 together form a central lumen enabling blood to be delivered from thedialysis machine to the patient. The transition from lumen 41 intonarrowed lumen 45, forms a stop or shoulder 43, the function of whichwill be described below.

Nose 42 also includes side arterial (delivery) openings 46 formedthrough the outer wall 44 wall in fluid communication with lumen 41,also functioning to return blood to the patient's body. Side openings orports 46 are preferably angled outwardly as shown to facilitate deliveryof blood in the direction of blood flow and lessen mechanical hemolysis.These additional openings help maintain the desired flow volume bydistributing the blood through multiple holes. Although only fouropenings are shown, it is contemplated that additional or fewer openingscan be provided and the openings can be axially displaced with respectto each other. Additional set(s) of openings can also be provided spacedproximally or distally from side openings 46.

In this embodiment, nose 42 forms the distal tip portion and is composedof a different material than the other portions of the catheter body 11and is welded or attached by other means to the catheter body 11. Thetip (nose) in this embodiment is composed of a stiffer material tofacilitate tunneling and blunt dissection through tissue. The nose couldalternatively be composed of a softer material, thereby being lesstraumatic upon contact with the vessel wall. However, in a preferredembodiment, the nose is composed of the same material as the catheterbody, having a small stiffener member embedded therein. Thisconfiguration is described in detail below in conjunction with FIGS.13-15.

Catheter 10 also has a series of venous (withdrawal) lumens 34 a-34 e,extending longitudinally along the length of the catheter body 11, eachterminating at surface 48 of nose 42. In the preferred embodiment, shownin the cross-sectional view of FIG. 8, the lumens 34 are oval-like inconfiguration, with opposite curved walls 37 a, 37 b and oppositesubstantially flat walls 39 a, 39 b. These spaced apart lumens havesolid material between them therefore increasing the structuralintegrity of the catheter body 11. The lumens 34 a-e are independentfrom one another through the distal, intermediate and proximal portions33, 35, 31 of the catheter body 11, until the hub 12 where the lumens 34a-34 e connect to a common connector tube. This is described in moredetail below. Lumens 34 a-34 e, as shown, are symmetrically positionedand radially displaced from the central arterial lumen 40.

With continued reference to FIGS. 5 and 6A, a series of side openings orports 50 are provided in the outer wall 14 of catheter body 10. Theseopenings 50 a, 50 b, 50 c, 50 d, and 50 e are each in fluidcommunication with a respective outflow lumen 34 a-34 e and are designedand configured to withdraw blood from the patient's body for delivery tothe dialysis machine. A second set of openings 52 a-52 e, spacedproximally from openings 50 a-50 e, is also in communication with arespective lumen 34 a-34 e. Only three of the side openings 50,52 areshown in FIG. 5, it being understood that the other three openings arepositioned on the other side of the catheter, preferably symmetricallyplaced to accommodate the circumferential arrangement of the venouslumens 34 a-34 e.

Although lumens 34 a-34 e are isolated along a substantial length of thecatheter, they preferably have a common flow source at the proximalportion 33 of the catheter 10. This is described in more detail below.

In the embodiment of FIG. 8, the arterial lumen size preferably rangesfrom about 0.006 inches to about 0.008 inches in cross-sectional area,and is more preferably 0.007 inches. The cross-sectional area of each ofthe venous lumens 34 preferably ranges from about 0.002 inches to about0.004 inches, and more preferably about 0.003 inches, bringing the totalcross-sectional area of the venous return lumens to about 0.01 inches toabout 0.02 inches, and more preferably about 0.015. This means that theratio of total cross sectional area of the arterial lumen to the venouslumen is about 1 to about 2.1. Other dimensions are also contemplated.

It should be appreciated that although five separate lumens 34 areshown, a fewer or greater number can be provided. Also, although twosets of side openings are shown (set 50 and set 52), a fewer or greaternumber of sets can be provided, and a fewer or greater number ofopenings in each set could be provided.

Alternative lumen configurations spaced circumferentially areillustrated in FIGS. 9A, 9B, 9C and 10. In FIG. 9B, three arc-shapedlumens 60 a, 60 b, 60 c are positioned around the arterial central lumen40′. These larger sized lumens provide for additional venous flow butresult in the reduction of the strength of the catheter wall due to theless wall material as compared to the lumen configuration of FIG. 8. InFIG. 9A, five lumens 66 a, 66 b and 66 c are provided. These lumens havemore of a rectangular (or trapezoidal) shape with one pair of opposingwalls having a straighter configuration than the lumen configuration ofFIG. 8. As shown, the other pair of opposing walls has a slightcurvature. In FIG. 9C, four oval-like venous lumens 76 a, 76 b, 76 c and76 d are positioned around a substantially square central lumen 78. Thislumen configuration provides for a substantially sized central lumen andsufficient room between the central lumen 78 and each of the venouslumens 76 a-76 d for the catheter walls to flex. In FIG. 10, five lumens70 a-70 e of circular cross-section are provided around the centrallumen 40″, adding to the stability of the catheter by increasing thewall material, but reducing the overall venous lumen size as compared tothe embodiment of FIG. 8. Preferably, the venous lumens in each of theseembodiments are independent from one another along the substantiallength of the catheter.

Fewer or greater number of lumens could be provided and lumens of otherconfigurations are also contemplated. This positioning of the venouslumens in a circle-like array around the catheter, i.e. radiallydisplaced from the center of the catheter, more evenly distributes thevacuum, as compared to a side by side venous/arterial lumenconfiguration, and ensures constant return flow since if one of thelumens becomes stuck against the vessel wall or otherwise clogged, theremaining lumens will maintain adequate flow. The openings in thesidewalls communicating with the lumens can also be elongated instead ofcircular, creating a series of longitudinally extending openings forentry of suctioned blood. This version of elongated openings is shownfor example in FIGS. 18 and 20 described in detail below.

To facilitate insertion, the catheter is configured to receive astiffening member in the form of a stiffening rod which stretches thecatheter to reduce its profile to aid in over the wire insertion andbetter navigate through small vessels. That is, the stiffening rod isinserted into central lumen 40 of catheter 10 and torqued to stiffen theflexible catheter for ease in over the wire insertion and navigationthrough the small vessels, and to reduce the outer diameter of thecatheter body by stretching it during insertion. After placement of thecatheter 10, the stiffening rod is removed, allowing the catheter toreturn to its higher profile position with the lumens of the necessarysize for blood transport to and from the body. Two embodiments of thestiffening rods are illustrated in FIGS. 4A and 4B and are shown priorto insertion into the catheter 10 in FIG. 3.

Turning to the first embodiment of the stiffening rod illustrated inFIG. 4A, the stiffening rod is designated generally by reference numeral80. Stiffening rod 80 has a distal tip 82, a proximal end portion 85 andan internal lumen 87 extending therethrough (see FIG. 11). Stiffeningrod 80 is inserted through the proximal end of inflow tube 16, in thedirection of the arrow of FIG. 11, over the guidewire 20 (which extendsthrough lumen 87 and through central lumen 40 until distal tip 82 abutsshoulder or stop 43 as shown in FIG. 12. The proximal end portion 85 ofstiffening rod 80 has a threaded portion 81 which is screwed onto screwthread 15 of inflow tube 16. This temporarily secures the stiffening rod80 within the catheter 10 during insertion. This threaded mountingrequires the stiffening rod 80 to be manually twisted, thereby torquingrod 80 as it presses forwardly and applies a force against shoulder(abutment surface) 43 to stretch the catheter body 11 to reduce itsouter diameter. It is contemplated in one embodiment, for example, thatthe catheter body 11 can be reduced in diameter from about 0.215millimeters to about 0.207 millimeters by the stiffening rod 80. (Othersize reductions are also contemplated). This reduction in catheter bodydiameter or profile is represented by the arrows D1 and D2 in FIGS. 11and 12, respectively, which show the change in dimension effectuated bythe stiffener rod 80.

After the catheter 10 is positioned at the desired site, the stiffeningrod 80 is unthreaded from the proximal thread 15 of inflow tube 16 andremoved from the central lumen 40 of the catheter 10 and from the inflowtube 16, thereby allowing the catheter to return to its normal profileof FIG. 11.

It should be appreciated that stiffening rod 80 can alternatively betemporarily attached at its proximal end to the inflow tube 16 by othermeans such as a bayonet lock, snap fit, etc. The rod could first bemanually twisted and then mounted by these various means for retentionin its torqued position.

An alternate embodiment of the stiffening rod is illustrated in FIG. 4Band designated generally by reference numeral 90. Stiffening rod 90 hasa threaded distal end 92 which is threaded onto internal threads 251 ofcatheter 200 shown in FIG. 6B. A series of proximal threads 91 arescrewed onto the threads 15 of the inflow tube 16 in the same manner asdescribed above for stiffener rod 80. The stiffening rod 90 functions inthe same manner as stiffening rod 80, i.e. to stretch the catheterduring insertion to reduce its profile and to stiffen it to facilitateinsertion, the only difference being the mechanical threaded attachmentof the distal end of the stiffening rod 90 to the catheter 200 insteadof the abutting relation of stiffening rod 80 with shoulder 43 ofcatheter 10. Preferably, the distal threads 92 are first threaded ontointernal thread 251, followed by attachment of the proximal threads 91as the stiffening rod 90 is torqued. Stiffening rod 90, like stiffeningrod 80, is preferably circular in cross-section, although otherconfigurations are also contemplated.

Catheter 200 of FIG. 6B is identical to catheter 200 in all respectsexcept for the threads 251 instead of shoulder 43 and lumen 241 which isuniform in diameter. Similar to catheter 10, catheter 200 has distalopening 247 and outflow side openings 246 in outer wall 244communicating with lumen 241 in distal tip portion 242, whichcommunicates with central lumen 40. Venous inflow lumens 234 a-234 eterminate at wall 248 and have respective side openings 252 a-252 e and250 s-250 e formed in the outer wall 214. Only one of the side openings250 a, 252 a are shown in the longitudinal cross-sectional view of FIG.6B.

As noted above, distal tip (nose) can be composed of a different stiffermaterial than the catheter body 11 or can be composed of a materialhaving a higher durometer than the catheter body. This stiffer materialwill facilitate both tunneling through and dilating tissue. In analternate preferred embodiment, however, the distal tip is composed ofthe same material as the catheter body but has a stiffening insert.

More specifically, the alternative nose (tip) configuration isillustrated in FIG. 15, with the method of manufacturing the tip shownin FIGS. 13 and 14. This nose or distal tip 104, is composed of the samematerial as the catheter body 108 and has a stiffening insert 110inserted through central lumen 106 of nose 104. Central lumen 106extends through the catheter body. The stiffening insert 110 ispreferably composed of the same material as the catheter body 11 andnose 104, except it is made of a harder durometer material such as 72shoreD vs. 85 shoreA for the catheter body 11. The material utilized canbe, by way of example, urethane. For convenience, only the distal tip isshown, the remaining portions of the catheter 100 being identical tocatheter 10.

The stiffening insert 110, preferably cylindrical as shown, has a hole112 for receipt of the guidewire and for communication with centrallumen 106. Insert 110 engages the inner wall surface 114 of centrallumen 106. Lumen 106, proximal of side openings 119, will include eithera stepped portion to provide an abutment surface (shoulder) forstiffening rod 80 or internal threads to mount stiffening rod 90 asdescribed above.

The method of manufacturing this bullet shaped nose 104 will now bedescribed in conjunction with FIGS. 13-15. Once cylindrical tube isformed, preferably by injection molding techniques, with centralarterial lumen 106 and venous lumens 109 a-109 e, stiffening insert 110is placed within central lumen 106 at the distalmost end andsubstantially flush with the distalmost edge 102 of the cylindricaltube.

Once the stiffening insert or slug 110 is placed within central lumen106, the tube is formed into the bullet nose shape of FIGS. 15A and 15B,by a conventional radiofrequency or other heating process which allowsthe tip material to flow and form around the harder insert 110. Afterheating of the die and formation into this configuration, the materialis cooled and thereby hardens to the configuration of FIG. 15 as thematerial fuses to the insert 110. A conventional core pin (not shown)can be used, inserted through the hole 112 and central lumen 106 duringthe forming process. When the material hardens, the pin is withdrawn tomaintain these openings. After the forming process, side holes 114 areeither cut or drilled through the wall 108 of catheter 100 tocommunicate with lumen 106 in the same manner as side holes 46communicate with central lumen 40 of FIGS. 1-6.

FIGS. 16A-17C illustrate two alternate embodiments of the catheter ofthe present invention having spacers to minimize contact of the catheterbody with the vessel wall. Provision of these spacers is optional. Inthe embodiment of FIGS. 16A-16C, catheter 150, similar to catheter 10,has a distal portion having a nose 154, a central arterial lumen 156which also receives a guidewire 20, and a series (e.g. 5) of venouslumens 160-160. Arterial lumen 156 communicates with lumen 151 andnarrowed lumen 153 of the nose 154, terminating in open distal end 158.A plurality of side openings 159 communicate with lumen 151 and functionin the same manner as side openings 46 of catheter 10. Venous lumens 160each terminate at side openings 161, similar to side openings 52 ofvenous lumens 34 of catheter 10. Although only one series of sideopenings 161 are shown, clearly additional arrays of side openings,positioned distally or proximally of side openings 161 could beprovided. The venous lumen configuration can also vary in a similarmanner as described above with respect to catheter 10. Thus, except forthe spacers, catheter 150 is identical to catheter 10.

A plurality of spacer wires 164 are embedded in the wall 169 of thecatheter 150 and are secured at region 158 by adhesive or other suitablemeans. In the normal configuration, spacer wires 164 bow slightlyoutwardly with respect to the outer wall 169 of the catheter 150 toreduce the likelihood of contact with the vessel wall. When thestiffening rod 80 is inserted over guidewire 20 and through centrallumen 156, as shown in FIG. 16C, and edge 170 is forced against theabutment surface or stop 159, the catheter body is stretched and thespacer wires 164 stretch to a straightened position, substantially flushwith the outer surface of wall 169. This reduces the profile of thecatheter and ensures the spacer wires do not interfere with catheterinsertion. When the stiffener rod 80 is withdrawn, the catheter returnsto its normal position, and the spacer wires 164 bow outwardly as inFIGS. 16A and 16B. It should be appreciated that stiffening rod 90 canalso be used with catheter 150 and would function to reduce the profilein the same manner as rod 80. Catheter 150 would then be provided withinternal threads for mounting stiffening rod 90 as described above.

An alternative to spacer wires is illustrated in FIGS. 17A-17C. Catheter180 is identical to catheter 150, except it is provided with integralribs 194 proximal of nose 184. That is, similar to catheter 150,catheter 180 has a central arterial lumen 186 configured to receiveguidewire 20 and stiffening rod 80 or 90. Lumen 186 communicates withlumen 181 and narrowed lumen 183 of the nose 184 which terminates inopen distal end 188. Side openings 189 of nose 184 communicate withlumen 181. A series of independent venous lumens 190 are provided,terminating in side openings 192, similar to side openings 161 ofcatheter 150. Although only one series of side openings 192 are shown,clearly additional arrays, positioned proximally or distally of sideopenings 192 could be provided.

Spacer ribs 194 are formed by cutout portions in the wall 193 of thecatheter 150. FIG. 17B illustrates the spacer ribs 194 in their normalposition, outwardly bowed from the outer surface of the wall 193 of thecatheter body. FIG. 17C illustrates the straightened or retractedposition of the spacer ribs 194, where the ribs 194 are substantiallyflush with the outer surface of wall 193, after stiffener rod 80 of FIG.4A (or rod 90 of FIG. 4B)) is inserted through central lumen 186 tostretch the catheter 150 for insertion in the manner described above.

FIGS. 18 and 19 illustrate another alternative embodiment of thecatheter of the present invention. Catheter 500 has a distal tip 502with a tapered region 510 transitioning to a reduced diameter region504. The central lumen terminates in distal opening 506 for fluiddelivery. Unlike the previously described embodiments, the distalopening 506 is the sole fluid delivery passageway into the body.However, it is also contemplated that additional side holes could beprovided in the tip to provide additional arterial ports for blooddelivery to the patient.

A series of venous openings 508 (only two are shown in the view of FIG.18) are provided in the transition or tapered region 510 of the tip 502.These openings are elongated to provide additional area for suctioning.Each of the openings 508 communicates with a respective venous lumen 510formed in the catheter. The venous lumen configuration (and arteriallumen configuration) can be in the form of those illustrated in FIGS.7-10, or other variations, as described above.

Stiffening rod 520 is shown positioned in the central lumen of thecatheter 500. Rod 520 is similar to the rods 80 and 90 described aboveexcept it extends distally of the distal tip 502 of catheter 500, has atapered distal end 524 to facilitate tunneling and dilating tissue, andhas a stepped portion to abut the internal structure of the catheter500. More specifically, guidewire 20 is shown extending through thecentral lumen of stiffening rod 520. The stiffening rod 520 is insertedthrough the central lumen of catheter 500 and the stiffening rod 520 andcatheter 500 are inserted over the guidewire 20, with the tapered tip524 facilitating passage of the catheter as it dilates tissue.

Catheter 500 has a cylindrical insert 514 positioned in the distal tip,similar to insert 110 of FIG. 13A. The insert 514 is composed of astiffer material to stiffen the tip of the catheter 500 to facilitateinsertion. Insert 510 has an opening to receive stiffening rod 520 asshown. Shoulder 526 formed by stepped portion 524 abuts the insert 514,thereby functioning as a stop in a similar manner that shoulder 43 actsas a stop for stiffening rod 80 shown in FIG. 11, the difference beingthe shoulder is formed in the internal wall of the catheter rather thanon the stiffening rod. Stiffening rod 520 thus acts in the manner as theaforedescribed rods 80, 90, i.e. pressing against the catheter tipportion to stretch the catheter for insertion, in addition to providinga tissue tunneling and dilation function.

FIG. 20 illustrates an alternative tip design of the catheter of thepresent invention. Catheter tip 602 has a bullet nose configuration,somewhat similar to the nose of FIG. 15, except having more of aprogressive taper. Catheter tip 602 also has a series of elongatedvenous holes 608 (only two are shown in the view of FIG. 20). In allother respects, e.g. stiffening insert, stiffening rod, distal blooddelivery opening 606, etc, catheter 600 is identical to catheter 500 ofFIG. 18.

The method of insertion of the catheter of the present inventionprovides an entire over the wire system. This is achieved by theprovision of trocar 300 illustrated in FIGS. 22 and 23. Trocar 300 has alumen 304 formed thererethrough (shown in phantom in FIG. 22)dimensioned for reception of guidewire 20. The lumen 304 extends theentire length of trocar 300, from a proximal opening 306 in handle 308to a distal opening 310 (shown in phantom in FIG. 22) on the undersideof the trocar 300 as viewed in FIG. 22. Distal opening 310 is adjacentthe distal tip 302, at the region where it bends slightly upwardly. Notethe lumen 304 of trocar 300 can be smaller than the outer diameter ofthe dialysis catheter, e.g. catheter 10, since it only needs to have aninternal diameter of about 0.045 inches to receive the guidewire. Thediameter of the catheter is typically 0.215 inches. The blunt distal tip302 of trocar 300 bluntly dissects tissue to create a subcutaneoustissue tunnel for subsequent securement of the catheter.

FIGS. 24A and 24B illustrate an alternate embodiment of the trocar.Trocar 380 is similar to trocar 300 except for an elongated ovalentrance opening 382 to lumen 383 for the guidewire and a beveled tip384 to facilitate tunneling through tissue. The handle configuration 386is also slightly different.

One method of use of the catheter will now be described in conjunctionwith FIGS. 25 to 28. The method will be described for inserting catheter10, however it should be appreciated that any of the aforedescribedcatheters can be inserted in the same manner.

First, needle “N” is inserted into the internal jugular vein to properlylocate the vessel and a guidewire 20 is inserted through the needle intothe right internal jugular vein “a” and into the superior vena cava “b”as shown in FIG. 25. The guidewire 20 is further advanced into the rightatrium “c”. The needle “N” is then withdrawn, leaving the guidewire 20in place, extending out of the patient's body at the proximal portion21.

Next, trocar 300 is inserted through a first incision “s” in thepatient, bluntly dissecting and tunneling under the skin, and forced outof the tissue at a second incision or site “u”, creating a subcutaneoustunnel “t” under the tissue as shown in FIG. 27. This provides a way tosecure the catheter as described below. Guidewire 20 is then threadedthrough lumen 304 of the trocar, with proximal portion 21 first insertedthrough trocar distal opening 310 so it emerges out of proximal opening306 as shown in FIG. 28A. Trocar 300 is then withdrawn from the body inthe direction of the arrow of FIG. 28B, leaving the guidewire 20 inplace as shown. Thus, guidewire 20 extends from the right atrium andsuperior vena cava, out through the right internal jugular vein andthrough the tissue tunnel “t”.

Catheter 10 is then threaded over the guidewire 20, with the proximalportion 21 of the guidewire 21 inserted through the distal tip lumen ofthe catheter, through the length of the central lumen, and through thehub 12 into the inflow tube 116 and out through fitting 15. The catheter10 is thus threaded over the wire, through the tissue tunnel “t” wherecuff 36 (not shown in FIG. 28C) is positioned in the tissue tunnel “t”to aid in securement of the catheter by enabling tissue ingrowth over aperiod of time. The catheter 10 is further advanced over guidewire 20down into the right internal jugular vein, into the superior vena cava,and into the right atrium. The guidewire 20 is withdrawn in thedirection of the arrow, leaving the catheter 10 in place for use asshown in FIG. 28C. Note the stiffening member 80 or 90 (not shown inFIG. 28C for clarity) is preferably utilized, i.e. inserted over theguidewire 20 through the fitting 15, inflow tube 16, hub 12, and centrallumen 40 to help guide the catheter 10 as described in detail above.

As can be appreciated, the catheter will be inserted in a similarfashion through the left internal jugular vein to be positioned asdepicted in FIG. 2. In this method, the subcutaneous tissue tunnel willbe formed on the left side as shown in FIG. 2, by the trocar 300, andthe catheter inserted over the guidewire through the subcutaneous tissuetunnel and through the left internal jugular vein and into the superiorvena cava and right atrium in the same way as described for right sideinsertion. It should be understood that any of the aforedescribedcatheters of the present invention can be inserted in this fashion.

An alternative method of insertion is illustrated in FIGS. 29A-29G. Inthis method instead of forming a second incision site adjacent theincision site through which the needle and guidewire are introduced intothe internal jugular vein as in FIG. 27, the trocar 300 emerges from theneedle/guidewire insertion site. Although catheter 10 is shown, any ofthe foregoing catheters can be inserted in the same manner.

In this method, the needle and guidewire are inserted in an identicalmanner as illustrated in FIGS. 25 and 26. After removal of the needle,the guidewire 20 is left in place extending outwardly from the incisionsite, designated by “w”. Next, as shown in FIG. 29A, trocar 300 isinserted through a first incision (as in FIG. 27) to create asubcutaneous tissue tunnel; however, unlike FIG. 27, trocar 300 does notemerge at a second incision site “u”. Instead, trocar 300 is advancedsubcutaneously to the needle incision site “w”, and emerges through thesite “w” as shown. Thus, as shown in FIG. 29A, the distal end of trocar300′ exits incision site “w” alongside the guidewire 20.

Guidewire 20 is then inserted (threaded) through the opening in trocar300 as described above and then the trocar is withdrawn through thetissue tunnel “t” and out through the first incision “s”, pulling theguidewire 20 through the tunnel. After the guidewire 21 is pulledthrough the tunnel “t” and out through incision “s”, the trocar 300 isremoved as shown in FIG. 29B, leaving the guidewire 20 in place. Notethe guidewire 20 is positioned to form a guidewire loop 22 to facilitateinsertion of the catheter as will be described below.

The catheter 10 is then advanced over the guidewire 20 (FIG. 29C),through the tissue tunnel, and exiting incision site “w” into theinternal jugular vein “a” (FIG. 29D). The catheter 10, as shown, isformed into a loop 13, tracking the loop 22 of guidewire 20, and thenadvanced downwardly through the internal jugular vein, the superior venacava and into the right atrium. (FIG. 29E). The guidewire 20 is thenwithdrawn as shown in FIG. 29F, and the catheter 10 is pushed downwardlyand/or pulled back to straighten the loop to position the catheter asshown in FIG. 29G.

It should be appreciated that formation of the loop in the guidewire andthe catheter is optional and the procedure can be performed without theloop.

FIG. 30 shows an alternate embodiment of a trocar utilized to retrievethe suture and retract it through the subcutaneous tissue tunnel. Trocar300′ is similar to trocar 300 of FIG. 29 except for the provision ofeyelet 312. The suture is threaded through the eyelet (shown as twosmall opposing holes in the wall at the distal end of the trocar 300′)and the trocar is pulled proximally through the tissue tunnel to pullthe suture out through incision “s”. As shown, the trocar extendsthrough incision “w”, the same incision created for insertion of theneedle and guidewire.

It should be understood that instead of an eyelet, a hook or other meanscan be provided on the trocar for holding the guidewire to enablepulling the guidewire through the tissue tunnel. That is, in theseversions, the guidewire is not threaded through the trocar lumen, butrather the trocar is utilized to pull (retract) the guidewire throughthe tissue tunnel.

FIG. 21 illustrates an alternative trocar used for a different approachto catheter insertion. This trocar, designated by reference numeral 350,does not provide for an entire over the wire system, however it is usedwith an approach providing a partial over the wire system whicheliminates the need for a tear way introducer sheath. As discussed inthe Background Section of this application, tear away introducer sheathsare currently being utilized to guide the dialysis catheter through thevessels into the right atrium. To avoid the problems associated with thetear away sheath, the catheter in this alternate method, can be advancedover a guidewire which can be placed in the manner illustrated in FIGS.25 and 26.

In this method, trocar 350 is attached to the distal end of the catheterby insertion of barbed end 352 into a mating fitting. Other means fortemporarily attaching the trocar are also contemplated.

Trocar 350 has a blunt distal tip 354 and is advanced through a firsttissue incision and out through a second tissue incision, bluntlydissecting tissue and forming a subcutaneous tissue tunnel in a similarmanner as described above, except without the guidewire. Since trocar350 is attached to the catheter, it pulls the catheter through thetissue tunnel, so it emerges out through the second incision. The trocar350 is then detached from the catheter. The catheter is then bent asnecessary and threaded over the guidewire into jugular vein, superiorvena cava, and right atrium.

Turning now to one method of manufacturing the hub of the catheter, andwith particular reference to FIGS. 31-37, a method is disclosed whichenables connection of the central arterial (delivery) lumen of thecatheter with an inflow tube and fluid connection of the fiveindependent venous (withdrawal) lumens with a single outflow tube toprovide fluid connection through the connectors.

Turning first to FIG. 31, a longitudinal slit 201 is formed at aproximal portion of catheter tube 203. FIG. 32 shows the relationship ofthe slit 201 and the central arterial lumen 205 as the slit is formed tocommunicate with the central lumen 205. As can be appreciated from thecross-sectional view of FIG. 33, the slit 201 is formed in the wall 206of the catheter tube 203 between adjacent venous (withdrawal) lumens 209a-209 e. Next, a metal pin 207 is inserted through the slit 201 for themolding process. Outer plastic inflow tubing 210 is placed over themetal pin 207 as shown in FIG. 35 to ultimately communicate with thecentral lumen 205. Outer plastic outflow tubing 211 is also shownpositioned over the catheter tube 203 which will communicate with thevenous lumens 209.

Next, conventional injection molding techniques are utilized so the softplastic material flows around the catheter tube 203 and the metal pin207 as shown in FIG. 36. Then, the material is cooled to harden, forminga hub 208, with the metal pin 207 removed to form lumen 204. Lumen 204has a narrowed region 202. As shown in FIG. 37, lumen 204 fluidlyconnects lumen 207 of inflow tube 210 with the central lumen 205 of thecatheter. Lumen 212 of outflow tubing 211 communicates with the fiveindependent venous lumens 209.

FIGS. 38-39 illustrate another method for manufacturing the catheterconnections. In this method, catheter body 402 of catheter 400 isseparated into five segments 401 a-401 e at its proximalmost end,corresponding to each of the venous (withdrawal) lumens 403 a-403 e.FIG. 40 illustrates the five cuts 408 made in the catheter wall 407between the adjacent venous lumens 403 to form the five segments 401.

A separate outflow connector tube 412 a-412 e is positioned within arespective venous lumen 403 a-403 e and is connected to a respectivesegment 401 a-401 e by solvent bonding or pressure fit. The proximal endof each connector tube 412 is positioned within outflow tube 414 whichtransports blood to the dialysis machine. Thus, blood flows through thevenous lumens 403, through each outflow connector tube 401 and into asingle outflow tube 414.

Inflow tubing 416 is connected to central arterial lumen by inflowconnector tube 410 which is attached inside the arterial lumen bysolvent bonding or pressure fit. Note that inflow connector tube 410 ispositioned between the segments 401. It should be understood, that iffewer or larger number of venous lumens are provided, then an equalamount of outflow tubes would be utilized as the venous lumens would becut into the corresponding number of segments.

FIGS. 41-43 illustrate another alternate method for manufacturing thehub of the catheter of the present invention. This hub and associatedtubing is illustrated for use with a catheter having the lumenconfiguration of FIG. 9C, although it can be utilized with other lumenconfigurations as well.

A central lumen connector (intermediate) tube 702 is joined with centrallumen 78 of catheter 700. Four venous connecting (intermediate) tubes704 are connected to a respective venous lumen 76 a. These tubes eachhave a lumen that is substantially circular in cross-section along itslength. The substantially circular lumens corresponds to thecross-sectional shape of the venous lumens within catheter 10 whichtransition from a substantially oval cross-sectional configuration to asubstantially circular cross-sectional configuration at the flaredproximal portion shown in FIG. 43. Note that arterial lumen 78 alsotransitions to a substantially circular cross-sectional configuration.

Each of the connector tubes 704 is connected to multi-lumen extension(outflow) tube 708 which provides outflow of blood to the dialysismachine. Extension tube 708 has a flared distal portion 711 with fourlumens 710, each configured for communicating with one of the connectortubes 704. As shown, each of the lumens 710 has a substantially circularcross-sectional configuration that transitions to a substantiallytriangular cross-sectional configuration towards the proximal portion.

Single lumen extension (inflow) tube 712, which provides inflow of bloodto the patient, connects to connector tube 702. Extension tube 712 has atapered distal end 718 and its lumen 719 transitions from asubstantially circular cross-sectional configuration to a substantiallysquare configuration toward the proximal end. Molding of housing 716with the foregoing tubes forms the catheter hub. Conventional tubeclamps, such as clamps 17 and 19 of FIG. 1, are placed around extensiontubes 708, 712 for cutting off blood flow.

A rotatable suture ring 720 is placed around the catheter hub andpreferably has a planar surface 722 to sit substantially flush with thepatient's skin. Suture holes 724 are configured to receive sutures forattaching the ring (and thus the catheter) to the patient.

The catheters described above can optionally include a surface treatmenton the exterior and/or the interior. The surface treatments can includefor example, an hydrophilic coating to increase lubricity and facilitateinsertion, a drug coating such as heparin or containing IIb, IIIainhibitors, inert coating substances such as Sorins carbon coating,and/or active coatings such as a silver ion coating.

It should be appreciated that although the catheter is described hereinas a dialysis catheter for hemodialysis, the catheter disclosed hereincould have other surgical applications, such as drug delivery or bloodsampling. Moreover, features of the catheter, tip configurations andlumen configurations can be utilized on other catheters.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the disclosure as defined by the claimsappended hereto.

1-25. (canceled)
 26. A system for placement of a catheter comprising adilating trocar and a catheter, the system comprising: a) a trocarhaving an elongated tubular portion and a lumen extending longitudinallythrough the tubular portion, the tubular portion terminating in adilating tip configured to dilate tissue and create a subcutaneoustissue tunnel, the lumen of the trocar having a first internal diameterand configured to removably receive a guidewire therethrough forretrieval of the guidewire through the tissue tunnel; and b) a catheterhaving a first lumen configured for blood delivery and a secondindependent lumen configured for blood withdrawal from the patient, atleast a portion of the catheter having an outer diameter configured forinsertion through the subcutaneous tissue tunnel, one of the lumens ofthe catheter configured to receive the guidewire for over the wireinsertion of the dialysis catheter through the tissue tunnel when thetrocar is removed.
 27. The system of claim 26, further comprising anelongated opening formed in the trocar communicating with the lumen ofthe trocar for insertion of the guidewire. 28-30. (canceled)
 31. Thesystem of claim 26, further comprising a stiffening member having alumen to receive the guidewire, the stiffening member insertable intothe catheter so the stiffening member and guidewire positioned thereinare both positioned in the catheter lumen.
 32. The system of claim 31,wherein the stiffening member is insertable into the first lumen of thecatheter.
 33. The system of claim 31, wherein the stiffening memberincludes threads at the proximal end for mounting the stiffening memberto the catheter.
 34. The system of claim 26, wherein the catheter has adistal portion of reduced diameter.
 35. The system of claim 34, whereinthe second lumen of the catheter terminates proximally of the firstlumen.
 36. A system for placement of a catheter comprising: a) acatheter having a first lumen configured for blood delivery to a patientand a second independent lumen configured for blood withdrawal from thepatient, at least a portion of the catheter having an outer diameterconfigured for insertion through a subcutaneous tissue tunnel, thecatheter configured to receive a guidewire which passes through thesubcutaneous tissue tunnel; and b) a stiffening member received in thecatheter such that the catheter with the stiffening member positionedtherein is inserted into the patient, at least a portion of thestiffening member configured to pass through the subcutaneous tissuetunnel.
 37. The system of claim 36, wherein the stiffening member isremovably secured to the catheter.
 38. The system of claim 36, whereinthe stiffening member is received in one of the lumens of the catheter.39. The system of claim 37, wherein the stiffening member has alongitudinally extending lumen to receive the guidewire.
 40. The systemof claim 37, wherein the stiffening member includes threads at aproximal portion for securement to the catheter.
 41. The system of claim36, further comprising a guidewire passing member to pass the guidewirethrough the subcutaneous tissue tunnel.
 42. The system of claim 36,wherein the second lumen of the catheter terminates proximally of thefirst lumen.
 43. The system of claim 42, wherein the distal portion ofthe catheter includes a reduced diameter region.
 44. The system of claim36, wherein the stiffener is positioned in the first lumen of thecatheter and has a lumen to receive the guidewire.
 45. The system ofclaim 36, wherein at least a portion of the first lumen is circular incross-section and at least a portion of the second lumen is non-circularin cross-section.
 46. The system of claim 45, wherein the second lumenterminates in an opening proximal of a distal opening of the firstlumen.
 47. The system of claim 45, wherein the stiffener is removablypositioned in the first lumen of the catheter.
 48. The system of claim36, wherein the catheter includes a spacer rib.
 49. The system of claim48, wherein the second lumen communicates with the patient proximal ofthe spacer rib.
 50. The system of claim 45, further comprising sideholes communicating with the first lumen.
 51. The system of claim 36,wherein the distal end of the catheter has an elongated reduced diameterregion, the first lumen extending through the reduced diameter region.52. The system of claim 51, wherein the first lumen terminates in adistal opening in the reduced diameter region and the second lumenterminates in an opening proximal of the distal opening.
 53. The systemof claim 52, wherein at least a portion of the first lumen is circularin cross-section and at least a portion of the second lumen isnon-circular in cross-section.